GNOMER is a program which solves the multigroup neutron diffusion equation in 1D, 2D and 3D cartesian geometry. The program is designed to calculate the global core power distributions (with thermohydraulic feedbacks), as well as power distributions and homogenized cross sections over a fuel assembly.

A simple thermohydraulic module to calculate temperature distribution is included. The Reactivity Coefficient method is applied for small corrections to cross sections when core conditions differ from nominal (at which the cross sections have been tabulated) due to thermohydraulic feedbacks. -Cyclic quadrant symmetry and octant symmetry options are available.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED: PC-DOS version 5
(PC); VMS, OpenVMS (VAX).

IAEA1271/03

The program was installed and executed by NEA-DB on: - VAXstation running under VMS 6.1 with the VAX FORTRAN compiler version 6.2; - on PC/P75 under Windows 95 and using the Lahey FORTRAN version 5.20. compiler.